Makes 12 medium Muffins or 8 large.
Cream butter and sugar, then cream banana into butter and sugar. Add flour and baking powder 2/3 cup and 1 tsp at a time, respectively, then add silk to moisten, a little at a time (use more than 3/4 cup if necessary). Add the blackberries with the last of the flour and milk, pour into greased muffin tins (or paper muffin cups in tins) and bake approx 25 minutes. Let rest 5 mins before removing from tins.